Field of the Invention
The present invention relates to a stand for a rolling mill where the passline is adjusted through a hydraulic force applying system having a hydraulic device in each of the housings of the stand. More particularly, it relates to a mounting arrangement thereof providing internal hydraulic passages in a manifold connected to a piston cylinder assembly, and which manifold extends through the housing and carries a transducer assembly for detecting the displacement of the piston cylinder assembly components, including a cradle assembly for easy handling of the hydraulic device and its transducer assembly in the stand.
A rolling mill roll stand normally consists of one or more devices for adjusting the roll gap between which material passes for its reduction. Such devices may be screw-down mechanisms and/or hydraulic force assemblies for setting the gap and applying pressure to at least one of the rolls to continually readjust the gap upon a variance in the gauge of the material passing between the work rolls which material causes a variance in the dimension of the roll gap.
Recently, hydraulic force applying systems have entirely replaced the screw-down mechanisms for gap and gauge control, i.e., for setting the gap and thereafter readjusting the gap for constant gauge control for the material, such as a steel strip.
In the stands employing a screw-down mechanism, the threaded spindle extends down through a bore in a housing, as exemplified in U.S. Pat. No. 4,083,213. In the past it was common to retrofit mills employing a hydraulic force applying system where several elongated bolts extending through the top of the housing affix the cylinder assembly to the housing in an upper area of a window of the housing. The hydraulic connections to the piston cylinder assembly are usually brought through the housing window, and being that these lines are long and flexible, they easily move around becoming entangled with the other hydraulic and electrical lines for the several mill stand components, thereby creating a hazardous and unsafe condition in the mill. In addition, these hydraulic lines to the force applying system reach into an awkward location in the housing interferring to an extent such that an optimal operation of the mill stand is substantially reduced.
In a hydraulic force applying system similar to that described in the immediately preceding paragraph, a position detecting means may be used to detect the displacement of either the piston or the cylinder, thus representing a change in the dimension of the roll gap. Oftentimes, this position detecting means is arranged such that it is exposed to the harsh environment which a rolling mill inherently engenders, thereby quickening the service life of the detecting means.
These present hydraulic force applying systems for controlling the roll gap consists of several short-lived items which require the system to be replaced quite frequently, for example, on an average of every three months. When considering that the rolling mill line consists of several stands, each which may carry a hydraulic gap system, it is readily appreciated that replacement and/or maintenance of the hydraulic system for each stand involves considerable downtime in that their removal involves an extensive, awkward operation due to the mounting arrangement for the hydraulic device and its hydraulic connections in the housing.
In the above-mentioned mounting designs where elongated bolts extending in the housing are used to mount the cylinder in the housing, the hydraulic system, if not supported, free falls down in the housing window, which condition can damage both the hydraulic device and other mill components as well as present a dangerous situation for the workmen. A mill operator must set the hydraulic device onto an auxiliary apparatus, such as a roll changing rig, or an overhead crane, or onto the lower back-up roll chock for removal therewith.